GB1310757A - Metal foil lead and manufacture thereof - Google Patents

Abstract

1310757 Making foil leads and incandescent lamps GENERAL ELECTRIC CO 19 May 1790 [29 May 1969] 24259/70 Heading B3A [Also in Divisions C7 and H1] A method of making a metal foil lead 1 for sealing into vitreous material comprises forming opposed notches in the opposite side edges of a short length of foil ribbon and etching one end portion 3 to feather the edges of the portion. Slotted molybdenum or tungsten foil strip 8, Fig. 13, is fed from a spool 32 to an electrolyte bath 15, which may comprise a sodium hydroxide solution. Etch resist coatings (14) may be applied to portions of the ends 3 to both sides of the strip 8, to one side only or on alternate sides of successive ends, Fig. 3 (not shown). The strip is passed through the bath 15, which includes copper electrodes 17, 18 connected to an A.C. supply 21. From the bath, the strip passes through a neutralizing acid bath 27, after removing the resist if applied, and then it is guided past water sprays 25. The strip may be passed through an alchol rinse bath (not shown), if required and it is dried by air jets 34. The treated strip may be cut into individual foil leads 1 or be wound on to a take-up spool 36 for subsequent severing. Alternatively the foil leads are cut from the strip prior to etching and etched individually. Making incandescent lamps.-The lamp filament 43 is secured by spud wires 44 to leads 30 welded to the foil leads 1 to form an assembly 31. The assembly is inserted into a quartz or quartz-like envelope 41 while it is held in a jig (not shown), which engages apertures 6 in the leads. Pinch seals 42 are formed and an inert gas, e.g. argon plus a small amount of a halogen such as iodine, bromine or compounds thereof, is introduced into the envelope 41. The exhaust tube 45 is tipped off and lugs 47 may be welded or clamped to the leads 1 to serve as terminals.